Candles are a common part of many winter holiday celebrations. Kids are particularly fascinated by these little bodies of heat and light. And with that fascination comes the inevitable questions: why? and how?
Why doesn’t the fire get bigger?
Why is there water in the candle?
How does it work?
Not long ago, a winter ice storm came along and knocked out our power. After the initial surprise of being plunged into total darkness, it seemed like the perfect chance for us to investigate just how candles work.
What you need:
- 8″ piece of cotton string
- metal butter knife
- paper towel
- small dish of water
- yellow or red food coloring
- 2 taper candles
- matches or lighter
Does the wick burn?
Does the wax burn?
It’s time to shift gears for a moment. Fill a small dish with water and add a couple drops of food coloring. Tear a paper towel into long narrow strips. Dip one end of a strip of paper towel into the dish and watch the colored water climb up the paper towel. This phenomenon is called wicking or capillary action and is the same thing that happens to the wick of a candle. A candle wick is made of absorbent material just like a paper towel.
When the hot flame from a match or lighter is held to a candle wick, the heat melts some of the candle wax. The liquid wax then travels up the wick by capillary action. When the liquid wax gets close enough to the heat of the flame, it is vaporized or converted to its gaseous state like when water is made into steam. The wax vapor is what burns.
Wax vapor burns
Be sure to work on a well-protected surface and wear eye protection, if possible, while using flame and hot wax.
This article was originally published in December 2013 by Home & School Mosaics.